Climate Change Past and Present
As our climate changes and the oceans warm, become increasingly acidic, and loose oxygen, it is increasingly important to understand how the changes we observe today compare to those in the Earth’s past. A primary goal of my research is to connect the past, present, and future of climate change using the microfossil record. Ongoing projects focus on (1) how East Pacific Oxygen Minimum Zones responded to rapid climate change through the last deglaciation, and (2) the spatial distribution of Oxygen Minimum Zones during the Pliocene, a period of stable warm climate.
Foraminiferal Abundances and Geochemistry
One of the best sources of information about past climates is the marine fossil record. In particular, the shells of foraminifera, single-celled marine organisms, represent one of the most widely used proxies for past environments, while simultaneously contributing to global carbon cycling. Understanding how these creatures respond to their environment is essential for a robust interpretation of their fossil record. Our lab studies changes in the geochemistry, morphology, and calcification of foraminifera in response to environmental variables (e.g. oxygen, temperature, and carbonate chemistry) on time scales of decades to millennia. Ongoing projects in this area are focused on (1) understanding how foraminiferal assemblages have changed in response to rapid ongoing climate change, and (2) linking the trace element composition of the shells from Oxygen Minimum Zone-dwelling foraminifera with their immediate environment.
In order to interpret environments of the past from foraminiferal shells, it is necessary to understand how and where in the water column they lived. This means situating planktic foraminifera in a greater ecological context. Active research in this area includes (1) using trace metal geochemistry to reconstruct microenvironment and (2) understanding changes in symbiosis during past periods of rapid warming and carbon increase.